A plant for turning sea water into fresh water was constructed in the vicinity of a seashore in order to obtain drinking water on an island and a desert region where there is only a small amount of precipitation. Furthermore, sea water is, for example, prime water for a plant making salt. In this type of sea water treatment plant, it is necessary to introduce a great amount of sea water into equipment for turning sea water into fresh water.
Furthermore, in a nuclear power generation plant, a great amount of cooling water is required. Therefore, in this type of power generation plant constructed in a place adjacent to a seashore, a great amount of sea water is required.
Therefore, conventionally, in such a sea water treatment plant and a power generation plant, sea water was taken in by a water intake structure shown in FIG. 7.
In the water intake structure illustrated in the same drawing, a water reservoir 1 is installed in the vicinity of a seashore, a water collecting portion 2 is installed on the sea bottom, and a water conveyance pipe 3 is used to connect the water reservoir 1 to the water collecting portion 2, wherein sea water taken into the water reservoir 1 is pumped up by a pump 4 and is distributed to various kinds of facilities.
A number of water intake pipes 4 protruding toward both sides of the water conveyance pipe 3 are provided at the water collecting portion 2. A number of through holes are provided on the respective water intake pipes 4, and a synthetic resin net or unwoven cloth is wound on the outer circumference thereof in order to prevent earth and sand from invading.
In such a water intake structure, usually, a water conveyance pipe 3 is buried by a driving method or a dig-sink method.
However, in such a conventional burying method of a water conveyance pipe 3, there existed the following shortcomings and problems in the technical aspects as described below.
That is, when burying a water conveyance pipe 3 by a driving method or a dig-sink method, many limitations in working exist, resulting from the surrounding vicinity of the place directly above the burying position of the water conveyance pipe 3 being exclusively occupied.
For example, in work carried out by the driving method in the sea, since sea water is to be shut out, it becomes necessary to guarantee fishery rights, and causes a hindrance in sea transportation.
Furthermore, when driving into the sea bottom, there is a fear that the sea will be polluted.
The invention was developed in view of such shortcomings and problems inherent to the conventional art, and it is therefore an object of the invention to provide a method for constructing a water intake pipe, which is able to construct a water intake pipe without exclusively occupying the surrounding directly above the work site during the construction.
Furthermore, it is another object of the invention to provide a method for constructing a water intake pipe, which does not adversely influence the surrounding environments of the work site during the construction.